Should Symptomatic Iliac Screws Be Electively Removed in Adult Spinal Deformity Patients Fused to the Sacrum?

Study Design. Retrospective, single-institution review of adult deformity patients who underwent iliac screw (IS) removal placed during fusion to the sacrum. Objective. To demonstrate whether IS removal offered benefit in terms of hip/buttock pain overlying the IS and whether IS could be removed without significant complications. Summary of Background Data. ISs are effective at countering cantilever forces imparted on sacral pedicle screws. Despite the efficacy of IS fixation, pain or implant prominence can lead to elective IS removal. There has been no study about IS removal in adult spinal deformity patients. Methods. A total of 395 consecutive walking adult spinal deformity patients fused to the sacrum with IS fixation and minimum 2-year follow-up met study inclusion criteria. Clinical/radiographical data were analyzed. Because there is no validated pain outcomes instrument specific to this situation, an 8-question IS removal questionnaire was designed and used for the sole purpose of this inquiry, within which a universally accepted numeric rating scale for pain was included. Results. Twenty-four of 395 (6.1%) patients (2 men and 22 women) with mean age of 50.5 +/- 10.8 years underwent elective IS removal at mean 2.6 +/- 1.3 years from index surgery. Mean follow-up from initial surgery was 6.3 +/- 4.0 years. Symptoms included hip/buttock pain in all 24 patients and IS prominence in 5 patients (20.8%). Screw removal was bilateral in 18 (75%) patients and unilateral in 6 (25%) patients. Using a numeric rating pain scale (0-10), hip/buttock pain improved after IS removal: preoperative 6.9 +/- 1.8, postoperative 2.0 +/- 2.7 (P < 0.05). Patients reported hip/buttock symptoms post-IS removal as "much improved" (78.3%), "somewhat improved" (8.7%), and "unchanged" (13.0%). Two of 24 (8.3%) patients sustained complications from IS removal (wound infection, n = 1; coronal/sagittal imbalance, n = 1). Presented with the same set of circumstances, 22 of 24 (91.7%) patients would have their IS removed again, including one of the patients who had a complication. Conclusion. Of 395 consecutive walking patients who had ISs placed during fusion to the sacrum for adult spinal deformity, 24 (6.1%) underwent elective removal. Patients had a statistically significant improvement in hip/buttock pain after IS removal, and a low prevalence of complications after the procedure was observed.